Lecture 32: Ear

Question 1

Answer 1

1. auricle
2. EOM
   3.tympanic membrane

Question 2

what is auricle made of

Answer 2

elastic cartilage, designed to direct sound waves into EOM

Question 3

external acoustic meatus

Answer 3

tunnel which is lined with normal skin (#2 in image)
○ Made of cartilage and bone
○ Blue represents cartilage. Lateral third is made of cartilage. Medial 2/3 is bone
○ Length = 1 inch
○ Skin lining is equipped with modified sweat gland, produce cerumen (ear wax)
§ Fxn cerumen: helps remove airborne particles & keeps insects away
○ Medial end = tympanic membrane

Question 4

cerumen

Answer 4

ear wax. produced by skin lining EOM. helps remove airborne particles

Question 5

tympanic membrane

Answer 5

ear drum. jxn btw outer and mid ear

Question 6

Answer 6

1.stapedius
2.tympanic membrane
3.malleus
4.incus
5.stapes
6.oval window
7.tensor tympani
8.round window

Question 7

joint btw malleus, incus, stapes.

fxn?

Answer 7

synovical. covered with hyaline cartilage

amplify/convey sound from tympanic membrane to inner ear

Question 8

auditory tube

Answer 8

connects middle ear to nasopharynx

Question 9

fxn tensor tympanic and stapedius

Answer 9

two small skeletal middle ear muscles
dampen sound

Question 10

where is inner ear

Answer 10

petours part of temporal bone

Question 11

bony labyrinth

Answer 11

contains perilymph
1.semicircular canals:three tubes opening to vestibule
2.vestibule: connects to middle ear via oval window and cochlea
3.cochlea: scala vestibuli and scala tympani

Question 12

oval window

Answer 12

part of middle ear connected to vestibule

Question 13

membranous labyrinth

Answer 13

suspended in bony labyrinth. membranous sacss and ducts, filled with endolymph

1.membranous semicircular ducts: in semicircular canal, open to utricle. dilated part=ampula, contains crista which have eq. sensors
2.utricle and saccule: inside vesituble. macula is elevation of saccule carries receptors
3.cochlear duct: carries organ of hearing “organ of corti”

Question 14

organ of hearing

Answer 14

organ of corti. within cochlear duct (one of the membranous labyrinth)

Question 15

Answer 15

1.vestibule
2.semicirular canal
3.semicircular duct
4.ampulla
5.saccule
6.cochlea
7.cochlear duct

Question 16

which receptors sensitized to movement of head in 3 dimensions

Answer 16

crista. within ampulla of semicircular canal

Question 17

which receptors sensitized to linear motion of head

Answer 17

The macula is an elevation in the saccule and saccule that
carries the equilibrium receptors.

Question 18

Answer 18

1.cochlea
2.spiral organ
3. cochlear duct
4. spiral ganlgion
5.cochlear branch CN VIII

Question 19

what is cochlea divided into

Answer 19

1. scala tympani
2. scala vestibuli
3. cochlear duct

Question 20

what is cochear duct filled with

Answer 20

endolymph

Question 21

what is btw the two scalas in the cochlea

Answer 21

perilymph

Question 22

Answer 22

1.tympanic membrane
2.auditory ossicles
3.oval winow
4.scala vestibuli
5.scala tympani
6.cochlear duct
7.round window

Question 23

explain passage sound thru ear

Answer 23

HEARING:
* Sound passes thru EOM, hit tympanic membrane = vibration
* Ossicles start to vibrate
* Passed to first connection btw mid and inner ear = OVAL WINDOW to the scala vestibuli of the cochlea (PERILYMPH)
* Vibration travels to end of scala vestibuli. Continuous with other scala (tympani)
* Vibration transmitted thru perilymph, continues down scala tympani
* Vibrations hit round window. Covered by elastic membrane. Absorbs vibrations
* As perilymph vibrates in the scalas, it vibrates cochlear duct, sandwiched btw the two scala
○ Vibration endolymph stimulates spiral organ
○ Converts mechanical vibrations to nerve impulses
Enters brain via CN VIII